Wohoo, picked up new silver/black sedan last night, very happy.

Has anyone did DYNO or noticed any difference by using 91/93 octane instead of regular 87?

The reason I ask is guys with 03 Accord (V6) show 10hp/10tq increase by using 93 instead of 87 so they push 250hp not 240 at the crank.

 

Congrats, the sedan is very nice, I had one for a day as a loaner. I thought it was 89 octane for the sedan, if not then I wasted $ by filling it up with 89 hehe.

Crawford Plenum / Z tube + Stillen Hi-Flow / Borla Dual Exhaust / Stillen Xdrilled+Stotted Rotors
Best 1/4 mile 14.371 @ 100.29, 60ft 2.347

 

Congrats on your new purchase, your gonna love it.

About the gas, thats wishful thinking on the honda guys part. Otherwise the Honda ECU must really retard the timing when it detects a knock. Patrick bedard of car and driver did a piece about octane and gasoline and came up in the end that unless you hear a pinging then your car should perform fine on 87 octane.



Jim
'03 Sedan
Brilliant Silver/Graphite
6MT/ Premium package
Sport tuned suspension
Aerodynamic Body Kit
Navigation and Satellite Radio

 

I have used the mid grade for almost a year now and it performs fine.

 

The 03 Accord EX-V6 was designed to run on 89 oct. It is also designed to increase the timing when using high oct. When I had My car ( lemoned), It dynoed at 206 W.H.P. indicating and increase, while using high oct. The Accord's drive train loss is about 22.5 % (estimated).

 

The owners manual clearly states that high octane 91 or above will improve performance which means the ECU is set up to advance the timing if you are using higher octane gasoline... I'd love to see a dyno with and without

2003.5 5AT Sedan Black/Black Premium/Winter Packages

 

Any engine will run better and be more efficient with higher octane, for the price difference you will get better mileage with higher octane, and your engine will last longer.
On the Coupe they recommend premium fuel.
Try it! measure performance and mileage and you will see the difference.

 

Not any engine. Some engines are designed, and the timing is set up for, regular 87 octane fuel. Engines set up this way will gain no benefit from higher octane fuels, as they don't have high compression ratios and won't advance their timing.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Ok all, here is some info for you how the ignition timing makes a difference comparing say 7th gen. Accord V6 (03+) to 6th gen (98-02).

The 7th generation Accords (03+) V6 ignition timing map is set for 91 or 93, and engine can still run fine on 87 octane because the knock sensor will pick up knock and retard the timing back to the point where the engine will run on 87 knock free. If you have 87 in the tank, the engine can only run so much timing before it starts getting knock. If you put 89 in, it can run a little more timing. Keep adding 91 or 93 octane until the ECU is up to its maximum advance levels and you'll see a better performance. Going higher octane however, 100+ is not needed because the engine is maxed out on the timing it's programmed to run and there is nothing more to gain.

In the case of the 6th gens Accords(98-02), since the engine is already at maximum timing and knock free on 87 octane fuel, that's why it will never gain any power from higher octanes. And since higher octane fuel burns at a slower rate, you need more timing advance to compensate for that which the 6th gen doesn't provide. That's why they lose power on higher octane fuels. Any fuel that's still burning when the piston is past about 20 degrees ATDC does not really contribute to power output and is pretty much wasted. That's why ignition timing is so critical. If your timing is too advanced you'll get knock. If it's too retarded the fuel will burn too late and the engine won't be efficient or responsive. So adding higher octane will not help anything on stock 6th gen Accord, it actually hurts.

The only exception is my supercharged 02 (6th gen) Accord V6 that has to run on 93 octane in order to bypass detonation since supercharged = much higher cylinder pressures = higher chance of knocking = increased need for octane content in fuel.

And finally, coming back to our G35. Its the same issue as the 7th gen Accord V6. By adding higher octane it should improve the performance (according to owners manual)as long as you not going higher then 93 on stock or light modded cars. I will try to do a DYNO with 87 then with 93 here in Chicago sometime early next year.

Thanks all for response. [img]/w3timages/icons/smile.gif[/img]

2004 G35s (bone stock)
-----------------------------------
2002 s/c Accord V6
1/4 13.9@101.8